The Binder cumulant [1]}, [2]} is a quantity used to
locate phase transition points and critical exponents. It is an
application of the finite size scaling
hypothesis [3]}, [4]}. In numerical simulations the
thermodynamic limit is not accessible, for this reason, phase
transition points can be shifted or smeared out when numerically
calculated based on susceptibilities or other response functions.
These numerical artifacts are eliminated at phase transition points by
the use of the Binder cumulant. The method is useful in
classical [5]} as well as quantum [6]} phase
transitions, however, heretofore the construction has only been
applied in phase transitions characterized by order parameters,
i.e. expectation values of Hermitian operators.
